Passiv.
The action without the doer.

In an active sentence, the subject does something. In a passive sentence, the subject receives something. The actor steps aside. The action takes center stage. German builds this with werden plus the Partizip II. That combination works in every tense and covers almost every situation where the passive is needed.

Aktiv vs. Passiv: the difference

In the active voice, the subject performs the action. The object receives it. In the passive voice, the former object becomes the subject. What was acted upon is now the topic of the sentence.

Aktiv	Passiv
DerArbeiter bautdasHaus.	DasHaus wird gebaut.
DerArzt untersuchtdenPatienten.	DerPatient wird untersucht.
Jemand bautdasHaus.	DasHaus wird gebaut.

The Akkusativ object of the active sentence becomes the Nominativ subject of the passive sentence. The actor either disappears or is mentioned separately with von.

The structure: werden + Partizip II

The formula is fixed. werden is conjugated and takes position two. The Partizip II moves to the end. Nothing changes between those two positions.

Subject	werden (pos. 2)	Middle	Partizip II (end)
DasBuch	wird		gelesen.
DerBrief	wird	heute	geschrieben.
DieFenster	werden	jeden Tag	geputzt.
DasAuto	wird	gerade	repariert.

For how Partizip II forms are built, including regular and irregular verbs: Perfekt. The spoken past.

Adding the actor: von + Dativ

In many passive sentences the actor is unknown, obvious, or irrelevant. When the actor matters and should be named, it is introduced with von followed by the Dativ. This is optional. The passive is grammatically complete without it.

• DasBuch wird von dem Lehrer gelesen. (The book is being read by the teacher.)
• DerBrief wurde von meiner Schwester geschrieben. (The letter was written by my sister.)
• DasHaus wird von einer Firma gebaut. (The house is being built by a company.)

The actor introduced with von is always in the Dativ. It is not the subject. It is an optional additional piece of information about who performs the action.

Passiv in different tenses

The passive works in every tense. Only werden changes its form. The Partizip II at the end always stays the same.

Tense	Formula	Example
Präsens-Passiv	wird + P.II	DasBuch wird gelesen.
Präteritum-Passiv	wurde + P.II	DasBuch wurde gelesen.
Perfekt-Passiv	ist + P.II + worden	DasBuch ist gelesen worden.

In the Perfekt-Passiv, the past participle of werden is worden, not geworden. This special form only appears in passive constructions. sein is always the auxiliary for the Perfekt-Passiv.

For werden as a change-of-state verb using geworden in Perfekt: werden. Three jobs, one verb.

When the subject is missing

When the action has no particular subject at all, the Passiv can appear without any subject. In this case, es often acts as a filler in position one, or another sentence element takes that slot.

• Es wird hier nicht geraucht. (Smoking is not done here.)
• Hier wird gearbeitet. (Work is being done here.)

The es at the start is not a real subject. It is a placeholder that fills position one when nothing else can. It disappears when another element takes position one.